Bad reputations tend to stick, even with foods. Continued negative press about a fruit, vegetable, or beverage is enough reason for many of us to banish it. Or maybe we indulge on occasion, but with a measure of guilt.

Eggs are inexpensive, contain the highest-quality protein on the planet and offer a lot of other nutrients.

Take avocados and peanuts, for example. Not too long ago they wore a big scarlet "F" for too much fat. Yet as peanuts and avocados sat languishing on many people's bad-for-you lists, researchers discovered that the fat in these two foods, mostly the monounsaturated kind, is extremely good for the heart--and for health in general. And the good news didn't stop there. Researchers continue to uncover disease-fighting chemicals or new health roles for these foods.

For the common mushroom, the "bad" reputation is a tad subtler. It's not perceived as unhealthy. But it is often dismissed as diet food, low in calories but with little to brag about nutritionally. Truth is, scientists are finding that mushrooms contain powerful compounds that boost immune function and may fight cancer.

Now that scientists are looking beneath the surface at mushrooms, avocados, and peanuts--as well as once-maligned eggs and coffee--redeeming qualities for each of these five foods are coming to light. They have nutritional respect and deserve a place at your table. All five are easy to enjoy on their own, or try them in our delicious recipes.

1. Peanut butter

Misconception: This creamy spread is an indulgence best enjoyed occasionally because it's high in fat and calories.

Why it's good for you:At least five major studies confirm that eating peanuts can lower risk for coronary heart disease. So it's no leap to think that peanut butter confers the same benefits. "Suffice it to say that eating peanut butter or peanuts has been associated with lower total cholesterol, lower ldl or 'bad' cholesterol, and lower triglycerides, all of which are associated with lower cardiovascular disease risk," says Richard Mattes, Ph.D., R.D., a professor of nutrition at Purdue University.

Even better, these health benefits seem to occur without also promoting weight gain. One reason could be that peanut butter is a stick-to-the-ribs kind of food. When Mattes offered a group of volunteers seven different snack foods (including peanut butter, rice cakes, pickles, and almonds), study participants reported that peanut butter or peanuts were much more filling snacks than rice cakes or pickles and tamed hunger for much longer. Sure, peanut butter is high in fat and calories, but if a small amount can quell hunger, that might explain why dieters seem more satisfied with weight-loss plans that include the spread.

But dieting or not, Mattes says a tablespoon or two of peanut butter is all it takes to net a world of benefits for both the heart and waistline. And don't obsess about peanut butter being a source of trans fats. A study by the U.S. Department of Agriculture finds no detectable trans fats in a standard 2 tablespoon serving. CookingLight.com: Nutrition faceoff: Peanut butter vs. cream cheese

2. Eggs

Misconception: Eggs are high in dietary cholesterol, so they don't have a place in my heart-healthy diet.

Why they're good for you: Eggs contain a variety of substances that appear to promote good health. Choline, a nutrient that is critical to brain function, is one example. Eggs, it seems, are one of the richest food sources of choline. Scientists at the University of North Carolina find adding choline to the diets of pregnant animals improves memory performance in their offspring. It may seem like a leap to apply this finding to people, but researchers are already encouraging pregnant women to eat eggs and other choline-rich foods (such as beef liver) during pregnancy.

Eggs are also being studied because they contain lutein and zeaxanthin, antioxidants that may keep eyes healthy and ward off the leading cause of blindness, macular degeneration. A recent report in the Journal of Nutrition suggests that we look at the egg as a whole package: Eggs are inexpensive, contain the highest-quality protein on the planet, and are loaded with small amounts of vital nutrients, including folate, riboflavin, selenium, B12, and choline. At 75 calories apiece, eggs are also a nutrient-dense food that makes a smart and low-calorie contribution to any menu.

3. Coffee

Misconception: The only thing you get from drinking coffee is a caffeine buzz.

Why it's good for you: The average cup of coffee has hundreds of different chemical compounds. Maybe that's why news reports about coffee vacillate between lauding its health benefits and labeling it harmful. Still, the benefits of coffee seem to outweigh the negatives.

To name just a few: Some Arizona researchers recently discovered that caffeinated coffee helps improve memory in older adults. A new study from the United Kingdom suggests that small amounts of coffee consumed throughout the day can increase alertness and improve performance on all kinds of tasks, including those that require hand-to-eye coordination and attention to detail. Preliminary studies suggest regular coffee drinking may lower risk of type 2 diabetes. A new report in the Journal of the American Medical Association finds that people who drink a daily four to six cups have a 28 percent lower risk of developing this illness--which is fast becoming an epidemic in this country--than folks who drink less than two cups each day. Researchers arrived at those numbers by pooling the results of nine different studies from the United States and around the world. Speculation is that caffeine deserves the credit, though it could be an antioxidant phenolic compound called chlorogenic acid. (If you drink several cups, spread them throughout the day to prevent the jitters, and avoid coffee late in the day, which can interfere with sleep.) CookingLight.com: Discover the perks of caffeine

4. Avocado

Misconception: I shouldn't eat avocados because they're high in fat.

Why they're good for you: A lot of attention centers on the fact that avocados are rich in monounsaturated fat, the heart-healthy kind. Yet scientists are now more interested in the active compounds in avocados that might help prevent cancer. One recent study found that those compounds can inhibit the growth of prostate cancer cells in the laboratory. While conducting the study, these researchers found avocados are loaded with a variety of antioxidants, including familiar disease-fighting compounds such as lutein, beta-carotene, and vitamin E.

Another recently discovered benefit is that avocados help the body absorb phytochemicals from other foods. Researchers from Ohio State University recently reported that pairing avocados with salsa or salad allows for better absorption of antioxidants in those foods. The lycopene in tomatoes or the beta-carotene in carrots may be better absorbed if there's a slice or two of avocado in the bowl. Scientists suspect that the fat content of avocados helps the body absorb these antioxidants. CookingLight.com: Good fats vs. bad fats

5. Mushrooms

Misconception: Mushrooms are a low-calorie food with little nutritional benefit.

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Why they're good for you: They may be 90 percent water and have only 18 calories per cup, but mushrooms are getting serious scientific attention. Laboratory reports and animal studies show that compounds in mushrooms may do everything from bolster immune function to suppress breast and prostate cancers to decrease tumor size. And now, Penn State researchers find that mushrooms, from the humble button to the giant portobello, harbor large amounts of an antioxidant called L-ergothioneine. The scientific buzz is that fungi, for the moment, are the only foods that contain this compound.

While scientists work to figure out how these findings will translate to dietary advice, there are plenty of reasons to enjoy mushrooms. Clare Hasler, Ph.D., a well-known expert in functional foods and executive director of the Robert Mondavi Institute for Wine and Food Science at the University of California, Davis, points out that mushrooms offer a healthy helping of the blood pressure-- lowering mineral potassium. "Most people might be surprised to learn that while orange juice is touted as one of the highest potassium foods, one medium portobello mushroom actually has more potassium," she says. "And five white button mushrooms have more potassium than an orange." E-mail to a friend